Patent EP-2579106-A1 (EP)
Title: Shaping of an integral transparent clock component
Inventor: POFFET CHRISTIAN
IPC: G04B29/02
Filed: 2011-10-04
Abstract: The method comprises selecting a first molding material for realization of a polymerizable transparent timepiece component, selecting polymethylsiloxane as a second molding material to realize a flexible mold for casting the first molding material, applying a gripping force to a bearing surface on a support plate (15), positioning the bearing surface at a distance from a first contact surface corresponding to a required thickness for the component, injecting the first material through an injection capillary network to fill a cavity defined by the contact surface of the plate. The method comprises selecting a first molding material for realization of a polymerizable transparent timepiece component, where the first material comprises a mixture of 78% trimethylolpropane (methacrylate), 19.5% pentaerythrityl tetraacrylate, 0.5% (4-tent-butylcyclohexyl) peroxydicarbonate, 2% 1-benzoylcyclohexanol and 0-50% additive, selecting polymethylsiloxane as a second molding material to realize a flexible mold for casting the first molding material, where a contact surface (7) of a plate (6) is negative to an upper surface, a flexible female mold (9) is formed in the second molding material, and the female mold comprises a first contact surface forming a female mold part on a lower surface, a first bearing surface cooperating with the contact surface of the plate around the first contact surface and a second bearing surface (13) opposite to the first contact surface, applying a gripping force to the second bearing surface on a support plate (15), positioning the second bearing surface at a distance from the first contact surface corresponding to a required thickness for the component, and exactly positioning relative to the first contact surface, where the contact surface of the plate faces the first contact surface and a first surface support in sealing contact with the contact surface of the plate, injecting the first molding material through an injection capillary network to completely fill a cavity defined by the contact surface of the plate, where the first contact surface and a flange are connected in a watertight manner by the first bearing surface on the contact surface of the plate, allowing to polymerize the first molding material injected into the cavity until the component is hard, where the plate is moved away from the support plate, and detaching the female mold from the component by deformation. The first material injection step is carried out at a temperature of 100-120[deg] C for 10-20 seconds. The method further comprises insolating the component by an UV radiation through the plate after injection of the first molding material. The cavity is polymerized to obtain of the hardness rigid component after extraction of the component. The gripping force is applied to the plate and the bearing plate during injection of the first molding material in the cavity and during polymerization of the first molding material for realization of the component. A node is inserted in the cavity before, during or after the injection of the first molding material, where the node comprises an electric and/or magnetic core. An independent claim is included for a transparent timepiece component.